Transcriptome Analysis Of Arginine Metabolism Pathway In Pre-hierarchical Follicles Of Zi Geese

The effect of high broodiness and seasonal breeding on most geese breeds lead to low eggs number as egg production trait of geese. Zi geese is world high egg production goose breeds and it has long laying period. Zi geese were used as model animal to study the mechanism of follicular development and will target control of the ovipository cycle of geese and increase egg production. It also can promote the development of the goose industry. Genes related to Arginine metabolism pathway and their metabolites play a role in geese follicular development. This study used transcriptome sequesing to understand the Arginine metabolism pathway in geese follicular development, the biological information of related genes, genes involved in signaling pathways and the expression tendency of relatd genes. Using five pre-hierarchical follicles of Zi geese(35~37 weeks old) laying in regular sequence, total RNA were extracted and sequenced with Illumina Hiseq 2500 platform which resulted in millions of reads(length, 150bp). At present, there is no suitable reference genome for the goose as they belong to non-model organism. Therefore, de novo assmebly was performed to obtain transcripts. ORF was used to predict the protein and nucleotide sequences of 145,020 transcripts. All the transcripts were tested by BlastX against the Nr, String, Swissprot, KEGG database. In this way, we understood the biological information of each transcript. The biological characteristics of genes are divided into three functional levels through GO annotation including biological process, molecular functions and cellular component. The three major branches can be more specifically classified, which is helpful to understnd the biological significance of gene in detail. The statistics showed the number of unigenes which was annotated to each functional level. The more active groups in biological process category were found in cellular process(74.74%), metabolic process(67.37%) and single-organism process(66.89%). The more active groups in molecular function category were observed to have binding(68.42%), catalytic activity(47.85%) and transporer activity(9.76%). The more active groups in cellular component category were found in cell(68.52%), cell part(68.52%) and organelle(56.75%). COG database were performed to annotate and classify gene function. The functions with the relatively large number of unigeses included signal transduction mechanisms(604), posttranslational modification, protein turnover, chaperones(479) and translation, ribosomal structure and biogenesis(282). The more active metabolic pathways in KEGG database were pathways in cancer(721 unigenes), the PI3K-Akt signaling pathway(688 unigenes), and the MAPK signaling pathway(660 unigenes). Arginine metabolism pathway and genes related to arginine metabolism were found using KEGG pathway. After GO enrichment analysis, we chose arginine, nitric oxide synthase and ornithine decarboxylas as the key genes to calculate their FPKM value of each gene as the expression quantity. The qRT-PCR was performed to identify the transcriptome results. The technique was performed to detect the expression tendency of the three genes in pre-hierarchical follicles. The results showed that the three genes in all 5 pre-hierarchical stages of geese follicles, with the highest expression in primary follicles.